一天一段scala代码（四）

为了更好的驾驭spark，最近在学习scala语言特性，主要看《快学scala》，顺便把一些自己认为有用的代码记下来。

package examples

object Example4 {

  def main(args: Array[String])
  {
      //不可变Map
      val scores= scala.collection.immutable.Map("linger"->1,"angela"->2)
      //scores+=("lanlan"->3)会报错

      //可变Map
      val scores2 = scala.collection.mutable.Map("linger"->9388296,"angela"->2)
      scores2+=("lanlan"->3) //增
      scores2-=("lanlan") //删
      scores2("linger") = 4 //改
      scores2("linger")  //查

      for((k,v)<- scores)  yield(v,k) //遍历,实现反转

      scores2.isDefinedAt("key")
      scores2.contains("key")

      val scores3 = new scala.collection.mutable.HashMap[String,Int]()
      val scores4 = new  scala.collection.mutable.LinkedHashMap[String,Int]()
      //还有各种map......

      //元组
      val t = ("linger","09388296","24")
      val name=t._1
      val num=t._2
      val age=t._3
      val (name2,num2,age2)=t
      println(name2,num2,age2)

      //zip操作
      val keys=Array("name","age")
      val values=Array("linger",24)
      val pairs = keys.zip(values)
      for((k,v)<-pairs) println(k,v)

      val map = pairs.toMap
      println(map)
  }

}

输出

(linger,09388296,24)
(name,linger)
(age,24)
Map(name -> linger, age -> 24)

本文链接：http://blog.csdn.net/lingerlanlan/article/details/43314409

本文作者：linger